Abstract

Spectrally encoded endoscopy (SEE) uses miniature diffractive optics to encode space with wavelength, allowing video-rate three-dimensional imaging through sub-millimeter, flexible endoscopic probes. Here we present a new approach for SEE in which the illumination and the collection channels are separated in space, and spectral encoding is present only in the collection channel. Bench-top experiments using spatially incoherent white light illumination reveal significant improvement in image quality and considerable reduction of speckle noise compared to conventional techniques, and show that the new system is capable of high sensitivity fluorescence imaging of single cells. The presented new approach would allow improved functionality and usability of SEE.

Figures (4)

Single channel spectral encoding. Schematic drawing of the optical paths in single channel space-to-wavelength encoding, illustrating the collection of a single wavelength from each lateral point on the sample.

Demonstration of different MC-SEE illumination configurations. a. An image of a paper resolution target using front illumination with visible light. b. Same as (a), using back illumination. c. A portion of a coin surface using spectrally encoded spatially coherent illumination in the near infrared (a Ti:sapphire laser). d. Same as (c), using wide field incoherent front illumination. Scale bars correspond to 1mm.